Nippon Steel Corporation

Masamitsu Wakoh

Hiroyuki Kondo

Koichi Chiba

Eiichi Takeuchi

Ryuji Uemori

Takehiko Toh

Akihiro Ono

Kazushige Umezawa

Tokio Suzuki

Katsuhiro Fuchigami

Yuichi Kato

Takashi Sawai

Kenzo Sawada

Katsuhiko Yui

Shozo Mizoguchi

Ryuichi Hiratsuka

Masatsugu Uehara

Junichi Kinoshita

Takashi Ishizawa

Haruo Kitamura

Tetsuo Nakamura

Daijiro Mizukoshi

In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by a fluorescent X-ray analysis method using an energy dispersion type spectroscope, or by other chemical or physical measurements, to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Evaluation apparatus for cleanliness of metal and method thereof

In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by dissolving the surface and extracting and filtering the inclusions to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Evaluation method for cleanliness of metal

Continuous-cast slab and steel product having dispersed fine particles

A method of oscillating a continuous caster mold at high frequencies comprises disposing a plurality of oscillators having substantially the same oscillating characteristic at appropriate intervals along or in the vicinity of a line where liquid metal contacts an inner lining of a mold, connecting the tip of each oscillator to the inner lining so that the axis of the oscillator extends at right angles to the surface of the inner lining, and supplying power from an oscillation generator to each oscillator so that the oscillation frequencies of any two adjoining oscillators are differentiated within the limit of 2 KHz. Thus, any two adjoining oscillators oscillate the inner lining at right angles to the surface thereof at mutually differentiated frequencies.

Method of oscillating continuous casting mold at high frequencies and

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Oita, Japan

Masamitsu Wakoh